Cause : INU-LSU comm loss comes when DDCS (fiber optic) communication between converters (for example, the inverter unit and the supply unit) is lost.

An AF80 warning in your ABB ACS880 drive indicates a communication loss between the drive control unit and the power unit. This disruption in communication can prevent the drive from operating correctly.

Note that the inverter unit will continue operating based on the status information that was last received from the other converter.

1. Check status of other converter (parameters 06.36 and 06.39).
2. Check settings of parameter group 60 DDCS communication.
3. Check the corresponding settings in the control program of the other converter.
4. Check cable connections. If necessary, replace cables.